Dielectric heat-transfer fluid

ABSTRACT

Provided is a use of a vegetable oil high in monounsaturates as dielectric and heat-transfer fluid in a device for the generation, storage, conversion and/or distribution of electrical energy.

FIELD OF THE INVENTION

The present invention relates to the field of dielectric heat-transferfluids, in particular dielectric fluid made from vegetable oils for usein, e.g. liquid filled transformers.

BACKGROUND OF THE INVENTION

Electrical transformers typically have windings of conducting wire whichmust be separated by a dielectric (i.e. non-conducting) material.Usually the coils and dielectric material are immersed in a fluiddielectric heat transfer medium to insulate the conductor and todissipate heat generated during operation. The heat-transfer medium mustact as a dielectric as well. In a typical arrangement, cellulosic and/oraramid paper or board is used as the dielectric material. Thecellulosic/aramid material is wrapped around the conducting wire, andused to separate the windings dielectrically, and may also be used as astructural support for the windings or other elements such as the cores.The fluid heat-transfer medium is typically an oil, which may be, forexample mineral oil or a sufficiently robust vegetable oil.

During use of the transformer, the dielectric material and heat-transferfluid are subjected to significant electromagnetic fields andsignificant variations of temperature and power surges and breakdowns.Over time, the relatively extreme conditions can lead to failure of thedielectric material and deterioration of the heat-transfer fluid.Deterioration leads to power loss due to dielectric loss, and mayeventually lead to discharges and catastrophic failure of thetransformer causing major pollution and/or fires.

The dielectric and heat-transfer fluid can furthermore be directly andindirectly degraded by oxygen migration and water formation oringression in the transformer.

Mineral oil generally shows excellent dielectric and heat-transferbehaviour, however, dielectric heat-transfer fluids are used in enormousquantities, (i.e. several hundreds of thousands of metric tons peryear). The public becomes increasingly sensitive to environment andsafety concerns around transformer units, and they are therefore subjectto more and more stringent regulations. Many heat-transfer fluidscurrently used (such as mineral oil) pose a serious concern since theyare flammable and do not biodegrade within reasonable time frame orsimply not at all. Fluids coming from “bio” (i.e. living) sources areincreasingly being seen as future fluids for those purposes. Forexample, U.S. Pat. Nos. 6,905,638 and 7,048,875 disclose transformersusing vegetable oils as the heat-transfer fluid. The vegetable oil maycontain chemically synthesised anti-oxidants.

A need remains for improved bio-degradable heat-transfer fluids, whichare not limited to food grade oils, showing good performance over time.

SUMMARY OF THE INVENTION

In a first aspect, the invention provides a use of a soy oil as aheat-transfer dielectric fluid in a device to generate, store, convertand/or distribute electrical energy, wherein the soy oil is one in whichat least 70%, preferably at least 75% of the fatty acids are C₁₄ to C₂₂mono-unsaturated, and less than 16%, preferably less than 7%, morepreferably less than 6% of the fatty acids are polyunsaturated.

In a second aspect, the invention provides a device to generate, store,convert and/or distribute electrical energy and/or optical signals,comprising:

(a) a conducting material;(b) a dielectric material; and(c) a heat-transfer dielectric fluid, which is a soy oil in which atleast 70%, preferably at least 75% of the fatty acids are C₁₄ to C₂₂mono-unsaturated, and less than 16%, preferably less than 7%, morepreferably less than 6% of the fatty acids are polyunsaturated.

In a third aspect, the invention provides a method for preconditioning aheat-transfer dielectric fluid which is a vegetable triacylglycerol,comprising the step:

(a) exposing said fluid to a constant and uniformly distributedelectromagnetic field.

In a fourth aspect, the invention provides a dielectric materialcomprising an organic fibrous structure (woven or non-woven)impregnated, with at least 1 wt % of a vegetable triacylglycerol,preferably a soy oil, in which at least 70%, preferably at least 75% ofthe fatty acids are C₁₄ to C₂₂ mono-unsaturated, and less than 16%,preferably less than 7%, more preferably less than 6% of the fatty acidsare polyunsaturated.

In a fifth aspect, the invention provides a use of a vegetable oil as aheat-transfer dielectric fluid in a device to generate, store, convertand/or distribute electrical energy, wherein the vegetable oil is atriacylglycerol having at least one hydroxy fatty acid.

In a sixth aspect, the invention provides a blended high oleic oil withan improved Df value at a constant temperature comprising:

a) a first oil in the range of 1-100 vol % that is a high oleic soybeanoil; andb) a second oil in the range of 1-100 vol %; andc) wherein the blended high oleic oil has an oleic acid content of atleast 70%; and wherein the Df value, at a constant temperature, of theblended high oleic oil is improved when compared under the sameconditions to an oil not comprising the high oleic soybean oil.

In a seventh aspect, the invention provides a blended high oleic oilwith an improved Df value at a constant temperature comprising:

a) a first oil in the range of 1-100 vol % that is a high oleic soybeanoil; andb) a second oil in the range of 1-100 vol % that is a mono-alkyl esterof oleic acid; andc) a third oil in the range of 1-100 vol %; andd) wherein the blended high oleic oil has an oleic acid content of atleast 70%; and wherein the Df value, at a constant temperature, of theblended high oleic oil is improved when compared under the sameconditions to an oil not comprising the high oleic soybean oil and/orthe purified esters of oleic acid.

BRIEF DESCRIPTION OF THE DRAWINGS AND SEQUENCE LISTING

FIG. 1 shows the dielectric loss factor (Df) vs temperature forcomparative fluids C1 (FR3) and C2 (Biotemp) and a fluid for useaccording to the invention, E1 (one of the oils of the invention,VGO-B1),

wherein the squares ▪ and triangles ▴ show the loss factor forcomparative fluid C1 (FR3) (measured at two different times), thecrosses X show the loss factor for comparative fluid C2 (Biotemp), thediamonds ♦ show the loss factor for a soybean oil for use according tothe invention E1 (VGO-B1), and the filled circles  show the loss factorfor mineral oil, which is included as a reference.

FIG. 2 shows the thermo-gravimetric pattern and heat flux generatedbefore (dotted lines) and after (solid lines) a pharmaceutical grade ofRicinoleic oil is exposed to the electromagnetic microwave treatment ofExample 8.

FIG. 3 shows the thermo-gravimetric pattern and heat flux generatedbefore (dotted lines) and after (solid lines) a commercial grade of HighOleic Sunflower oil, the comparative fluid C2, is exposed to theelectromagnetic microwave treatment of Example 8.

FIG. 4 shows the thermo-gravimetric pattern and heat flux generatedbefore (solid lines) and after (dotted lines) a commercial grade ofnormal soybean oil, the comparative fluid C1, was exposed to theelectromagnetic microwave treatment of Example 8.

FIG. 5 shows the thermo-gravimetric pattern and heat flux generatedbefore (solid lines) and after (dotted lines) the fluid for the use ofthe invention, E1, was exposed to the electromagnetic microwavetreatment of Example 8.

FIG. 6 shows the thermal behaviour of untreated Kraft paper (solidline), Kraft paper imbibed with the fluid for use according to theinvention (dotted lines) and Kraft paper imbibed with the fluid for useaccording to the invention and pre-treated with microwaves according toExample 8 (dash-dot lines).

FIG. 7A shows the Df value measured vs temperature for soy oils for useaccording to the invention, E2, such as “HOSO”; designated by squaresand high oleic soy oil having 70%, oleic acid and 16% polyunsaturates(designated by triangles), compared to soy oils having 21% oleic acidand 61% polyunsaturates (“Cm”; designated by X's), 65% oleic acid and20% polyunsaturates (designated by diamonds).

FIG. 7B shows the DF value measured vs temperature for soy oils for useaccording to the invention. The crosses designate the results for E4,having 74.36% oleic (74%);

The X's designate the results for the commodity soy oil (Cm) having21′)/0 oleic acid and 61% polyunsaturates.The triangles designate the results for a soy oil blend having 70% oleicand 16% polyunsaturates.The diamonds designate the results for a soy oil blend having 65% oleicand 20% polyunsaturates.

FIG. 8 shows the variation of Df vs oleic acid content for blended soyoils at two different temperatures (upper line: 130° C.; lower line: 90°C.).

FIG. 9 shows the dielectric loss factor (Df) vs temperature forcomparative fluids C1 (FR3) and C2 (Biotemp) and two oils for useaccording to the invention, E2 (E1, VGO-B1) and E4 (E1, VGO-B2).

wherein the squares  show the loss factor for comparative fluid C1, theopen triangles ▴ show the loss factor for comparative fluid C2, thediamonds ♦ show the loss factor for a soybean oils for use according tothe invention E2 and E4.

FIG. 10 depicts fragment PHP19340A.

FIG. 11 depicts fragment PHP17752A.

FIG. 12 depicts plasmid PHP19340.

FIG. 13 depicts plasmid PHP17752.

SEQ ID NO: 1 sets forth the nucleotide sequence of plasmid PHP19340A.

SEQ ID NO: 2 sets forth the nucleotide sequence of plasmid PHP17752A.

SEQ ID NO: 3 sets forth the nucleotide sequence of plasmid PHP19340.

SEQ ID NO: 4 sets forth the nucleotide sequence of plasmid PHP17752.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The expressions dielectric loss factor, dielectric loss value, Df value,Df, or dielectric dissipation loss are used interchangeably herein. Dfand Tan delta are frequently quoted in the literature as beingequivalent.

The expression “E1” is directed to all the high oleic soy oils of theinvention and includes the range of the fatty acid compositions shown inTable 1 and includes without limitation the following oils: VGO-B1,VGO-B2, HOSO, the 70% oleic soybean oil shown in Table 6, E2, and E4.

Methods

Fatty acid contents of oils may be determined using gas chromatographywith flame ionization detection, or reverse-phase liquid chromatographywith fluorescence detection. Percentages quoted relate to relativepercent expressed as %, i.e. the area under the peak of one specificfatty acid divided by the sum of the peak areas of all fatty acid in aparticular sample, unless stated otherwise.

Tocopherol content of oils is determined using an HPLC method.

The inventors found that a soy oil having a relatively high (i.e. atleast 70%, preferably at least 75% of the fatty acids) content ofmonounsaturated C₁₄ to C₂₂ fatty acids, and less than 16%, preferablyless than 7%, more preferably less than 6% of polyunsaturated fattyacids, gives particularly good performance as a heat-transfer dielectricfluid.

More preferably, the soy oil for use according to the invention has atleast 80% content of monounsaturated C₁₄ to C₂₂ fatty acids,particularly preferably at least 82%, preferably at least 84% content ofmonounsaturated C₁₄ to C₂₂ fatty acids, or at or about 85% content ofmonounsaturated C₁₄ to C₂₂ fatty acids.

More preferably, the soy oil for use according to the invention has lessthan 4% of polyunsaturated fatty acids.

In a preferred embodiment, the soy oil for use according to theinvention has at least 80% content of monounsaturated C₁₄ to C₂₂ fattyacids, and less than 4% of polyunsaturated fatty acids.

More preferably, the monounsaturated fatty acids are C₁₈ monounsaturatedfatty acids. Most preferably, they are oleic acid.

More preferably, the polyunsaturated fatty acids are C₁₈ fatty acidshaving two or three double bonds, for example C18:2 and/or C18:3.

Preferably C18:2 is less than or equal to 5%.

More preferably, the soy oil has a C18:1 content of greater than about75% of the fatty acid moieties, and a combined C18:2 and C18:3 contentof less than 7%, more preferably less than 6% of the fatty acid.

In a preferred embodiment, the soy oil has a saturated fatty acidcontent of less than at or about 12%, more preferably less than at orabout 10%. Higher saturated fatty acid content leads to an undesirablehigher pour point, and diminished dynamic heat transfer ability.

In a particularly preferred embodiment, the soy oil has the followingfatty acid content: at or about 6% C16:0, 3% C18:0, 86% C18:1, 2% C18:2and 0-2% C18:3.

In another particularly preferred embodiment, the soy oil has thefollowing fatty acid content: at or about 6% C16:0, 4% C18:0, 79% C18:1,4% C18:2, 2% C18:3.

In another preferred embodiment, the soy oil has the following fattyacid content: at or about (see table below):

Fatty acid % C14:0 (myristic) 0.04 C15:0 (pentadecanoic) 0.03 C16:0(palmitic) 6.15 C16:1 n-7 (palmitoleic) 0.10 C17:0 (margaric) 0.81 C18:0(stearic) 3.85 C18:1 n-9 (oleic) 77.74 C18:1 (octadecenoic) 1.30 C18:2n-6 (linoleic) 4.20 C18:3 n-3 (alpha-linoleic) 2.19 C20:0 (arachidic)0.39 C20:1 n-9 (eicosenoic) 0.38 C20:1 n-9 (eicosadienoic) 0.40 Totalpolyunsaturates 6.79 C22:0 (behenic) 0.01 C24:0 (lignoceric) 0.16 Others0.90

The soy oil preferably has a water content of less than at or about 300ppm.

In a preferred embodiment, the soy oil additionally comprises tocopherolantioxidants. Preferably the tocopherols are present at a concentrationof at least 85 mg/100 g of oil, more preferably at least 100 mg/100 g ofoil, as measured by a known HPLC method. The tocopherol may be selectedfrom naturally occurring tocopherols, in particular alpha-, beta- andgamma- and delta-tocopherols, and mixtures of these.

In a particularly preferred embodiment, the soy oil has a tocopherolcontent as measured by a known HPLC method of at or about 160 mg/100 goil, and has the following fatty acid content: at or about 6% C16:0, 3%C18:0, 86% C18:1, 2% C18:2 and 2% C18:3.

In another particularly preferred embodiment, the soy oil has atocopherol content as measured by a known HPLC method of at or about 160mg/100 g oil, and has the following fatty acid content: at or about 6%C16:0, 4% C18:0, 79% C18:1, 4% C18:2, 2% C18:3.

The tocopherol is preferably tocopherol which is present in the soy oilor in any other vegetable oil as derived from the plant source or innatural plant extracts, NPE (i.e. as opposed to synthesized tocopherolthat is added).

The soy oil may additionally comprise additives known in the art, whichcomprise generally less than 5 wt % of the dielectric heat-transferfluid, for example: bactericides, metal chelators, corrosion inhibitors,antioxidants, heat-stabiliser, viscosity adjusters, pour pointdepressants, including natural plant extract promoting thosefunctionalities etc.

The soy oil for use according to the invention can be blended with otherfluids used for dielectric heat-transfer fluids, such as other vegetableoils, mineral oil, etc.

In a particularly preferred embodiment, the oil is derived from soybeansprepared by recombinant manipulation to give increased expression of theactivity of the gene encoding oleoyl 12-desaturase.

An exemplary description of a suitable genetic manipulation in soybeansis described in U.S. Pat. No. 5,981,781 (E.I. du Pont de Nemours andCompany), and is detailed below:

In soy (Glycine max) there are two genes encoding oleoyl 12-desaturaseactivity, one of which (GmFad 2-1) is expressed only in the developingseed (Heppard et al. (1996) Plant Physiol. 110:311-319). The expressionof this gene increases during the period of oil deposition, startingaround 19 days after flowering, and its gene product is responsible forthe synthesis of the polyunsaturated fatty acids found in soybean oil.GmFad 2-1 is described in detail by Okuley, J. et al. (1994) Plant Cell6:147-158 and in WO94/11516. It is available from the ATCC in the formof plasmid pSF2-169K (ATCC accession number 69092). The other gene(GmFad 2-2) is expressed in the seed, leaf, root and stem of the soyplant at a constant level and is the “housekeeping” 12-desaturase gene.The Fad 2-2 gene product is responsible for the synthesis ofpolyunsaturated fatty acids for cell membranes.

GmFad 2-1 was placed under the control of a strong, seed-specificpromoter derived from the α′-subunit of the soybean (Glycine max)beta-conglycinin gene. This promoter allows high level, seed specificexpression of the trait gene. It spans the 606 by upstream of the startcodon of the α′ subunit of the Glycine max β-conglycinin storageprotein. The β-conglycinin promoter sequence represents an allele of thepublished β-conglycinin gene (Doyle et al., (1986) J. Biol. Chem.261:9228-9238) having differences at 27 nucleotide positions. It hasbeen shown to maintain seed specific expression patterns in transgenicplants (Barker et al., (1988) Proc. Natl. Acad. Sci. 85:458-462 andBeachy et al., (1985) EMBO J. 4:3047-3053). The reading frame wasterminated with a 3′ fragment from the phaseolin gene of green bean(Phaseolus vulgaris). This is a 1174 by stretch of sequences 3′ of thePhaseolus vulgaris phaseolin gene stop codon (originated from clonedescribed in Doyle et al., 1986).

The GmFad 2-1 open reading frame (ORF) was in a sense orientation withrespect to the promoter so as to produce a gene silencing of the senseGmFad 2-1 cDNA and the endogenous GmFad 2-1 gene. This phenomenon, knownas “sense suppression” is an effective method for deliberately turningoff genes in plants and is described in U.S. Pat. No. 5,034,323.

For maintenance and replication of the plasmid in E. coli the GmFad 2-1transcriptional unit described above was cloned into plasmid pGEM-9z (−)(Promega Biotech, Madison Wis., USA).

For identification of transformed soybean plants the β-glucuronidasegene (GUS) from E. coli was used. The cassette used consisted of thethree modules; the Cauliflower Mosaic Virus 35S promoter, theβ-glucuronidase gene (GUS) from E. coli and a 0.77 kb DNA fragmentcontaining the gene terminator from the nopaline synthase (NOS) gene ofthe Ti-plasmid of Agrobacterium tumefaciens. The 35S promoter is a 1.4kb promoter region from CaMV for constitutive gene expression in mostplant tissues (Odell et al. (1985) Nature 303:810-812), the GUS gene a1.85 kb fragment encoding the enzyme β-glucuronidase (Jefferson et al.(1986) PNAS USA 83:8447-8451) and the NOS terminator a portion of the 3′end of the nopaline synthase coding region (Fraley et al., (1983) PNASUS 80:48034807). The GUS cassette was cloned into the GmFad 2-1/pGEM-9z(−) construct and was designated pBS43.

Plasmid pBS43 was transformed into meristems of the elite soybean lineA2396, by the method of particle bombardment (Christou et al., (1990)Trends Biotechnol. 8:145-151). Fertile plants were regenerated usingmethods well known in the art.

From the initial population of transformed plants, a plant was selectedwhich was expressing GUS activity and which was also positive for theGmFad 2-1 gene (Event 260-05) when evaluated by PCR. Small chips weretaken from a number of R1 seeds of plant 260-05 and screened for fattyacid composition. The chipped seed was then planted and germinated.Genomic DNA was extracted from the leaves of the resulting plants andcut with the restriction enzyme Bam HI. The blots were probed with aphaseolin probe.

From the DNA hybridization pattern it was clear that in the originaltransformation event the GmFad 2-1 construct had become integrated attwo different loci in the soybean genome. At one locus (Locus A) theGmFad 2-1 construct was causing a silencing of the endogenous GmFad 2-1gene, resulting in a relative oleic acid content of about 85% (comparedwith about 20% in elite soybean varieties). At locus A there were twocopies of pBS43. On the DNA hybridization blot this was seen as twocosegregating bands. At the other integration locus (Locus B) the GmFad2-1 was over-expressing.

Fourth generation segregant lines (R4 plants), generated from theoriginal transformant, were allowed to grow to maturity. R4 seeds, whichcontained only the silencing Locus A (e.g., G94-1) did not contain anydetectable GmFad 2-1 mRNA (when measured by Northern blotting) insamples recovered 20 days after flowering. GmFad 2-2 mRNA, althoughreduced somewhat compared with controls, was not suppressed. Thus theGmFad 2-1 sense construct had the desired effect of preventing theexpression of the GmFad 2-1 gene and thus increasing the oleic acidcontent of the seed. All plants homozygous for the GmFad 2-1 silencinglocus had an identical Southern blot profile over a number ofgenerations. This indicates that the insert was stable and at the sameposition in the genome over at least four generations.

The soy oil is extracted from the plant source using known methods ofextraction. Preferred methods of extractions are those that avoid stepsthat result in destruction of the natural tocopherol content. Forexample, it is preferred to avoid heating the oil to above 200° C. forprolonged periods, for example during deodorization steps which can bereduced or eliminated. In some instances it might be preferred to avoidhydrogenation.

It is also preferred to take fractions of the oil, which are “first”extracted meaning prior to a more exhaustive extraction of the oil outof the seed. Physical extraction is preferred over solvent extraction orany combined extraction process, which privileges the physicalextraction step.

Methods for the extraction and processing of soybean seeds to producesoybean oil and meal are well known throughout the soybean processingindustry. In general, soybean oil is produced using a series of stepswhich accomplish the extraction and purification of an edible oilproduct from the oil bearing seed. The oils of the invention are notlimited to food-grade oils. Soybean oils and soybean by-products areproduced using the generalized steps shown in the diagram below.

Soybean seeds are cleaned, tempered, dehulled, and flaked whichincreases the efficiency of oil extraction. Oil extraction is usuallyaccomplished by solvent (hexane) extraction but can also be achieved bya combination of physical pressure and/or solvent extraction. Theresulting oil is called crude oil. The crude oil may be degummed byhydrating phospholipids and other polar and neutral lipid complexeswhich facilitate their separation from the nonhydrating, triglyceridefraction (soybean oil). The resulting lecithin gums may be furtherprocessed to make commercially important lecithin products used in avariety of food and industrial products as emulsification and release(antisticking) agents. Degummed oil may be further refined for theremoval of impurities; primarily free fatty acids, pigments, andresidual gums. Refining is accomplished by the addition of caustic whichreacts with free fatty acid to form soap and hydrates phosphatides andproteins in the crude oil. Water is used to wash out traces of soapformed during refining. The soapstock by-product may be used directly inanimal feeds or acidulated to recover the free fatty acids. Color isremoved through adsorption with a bleaching earth, powdered activatedcarbon and/or synthetic neutral resin. Which removes most of thechlorophyll and carotenoid compounds. Deodorization which is principallysteam distillation under vacuum, is the last step and is designed toremove compounds which impart odor or flavor to the oil. A more detailedreference to soybean seed processing, soybean oil production andby-product utilization can be found in Erickson, 1995, PracticalHandbook of Soybean Processing and Utilization, The American OilChemists' Society and United Soybean Board.

A second aspect of the invention provides a device to generate, store,convert and/or distribute electrical energy with or without opticalsignals therewith, comprising:

(a) a conducting material;(b) a dielectric material; and(c) a heat-transfer dielectric fluid, which is a soy oil in which atleast 70%, preferably at least 75% of the fatty acids are C₁₄ to C₂₂mono-unsaturated, and less than 16%, preferably less than 7%, morepreferably less than 6% of the fatty acids are polyunsaturated.

The heat-transfer dielectric fluid used in the device of the inventionmay be any of the preferred oils for use in the invention describedherein and any mixtures thereof.

In a preferred embodiment, the device is a transformer. Typically, thetransformer will have conducting material in the form of coils orwindings of conducting wire and connections (e.g. copper, aluminium,iron, steel, silver, etc.). The conducting material is wound around andcovered in the dielectric material, which is typically chosen from wovenor non-woven fibrous material, films and laminates, such as paper, boardand/or multidimensional structures. The paper or board may be cellulosicor it may be, for example, composed of aramid fibres, preferablym-aramid fibres, polyimides, polyphenylsulfones, polyamides, polyesters(e.g. PET) and polyethylene, and combination therewith in various formscomposites, laminates and tailored morphologically tailored surfacesand/or multidimensional structures and hybrids/mixtures thereof. Theconducting material and the dielectric material are placed in areceptacle and the dielectric heat-transfer fluid is added to submerseor partially submerse the components. Alternatively, the dielectricmaterial (e.g. paper or board) is impregnated with the dielectricheat-transfer fluid by absorption (“imbibing”) at various stages of itsprocessing.

In another preferred embodiment, the dielectric heat-transfer fluid maybe used for example in a generator, a capacitor, an inverter or electricmotor, a switch and cables.

A third aspect of the invention is a method for preconditioning aheat-transfer dielectric fluid which is a vegetable triacylglycerol,comprising the step:

(a) exposing said fluid to a constant and uniformly distributedelectromagnetic field. The electromagnetic field may be appliedcontinuously or in series of constant and/or variable pulse andrelaxation sequences; repeating the exposure as often as needed.

The beneficial effect of the pre-treatment extends to alltriacylglycerol dielectric heat-transfer fluids and mixtures thereof,and is not limited to the fluid used in the use according to theinvention.

In a preferred embodiment, the electromagnetic field is applied in theform of microwaves.

Preferably the electromagnetic field is applied at sufficient power andfor a sufficient period of time to treat the vegetable triacylglycerolto at least at or about 100° C., preferably at least at or about 120°C., but not higher than at or about 170° C., more preferably not higherthan at or about 160° C. It is particularly preferred to heat thevegetable triacylglycerol to at or about 140° C.

After exposing the fluid to the electromagnetic filed, it is allowed tocool.

In one embodiment, the vegetable triacylglycerol is exposed to theelectromagnetic field as a neat fluid (i.e. in a suitable receptacle),and then used as desired. In another embodiment, the vegetabletriacylglycerol is first applied to an absorbent dielectric material,such as paper (e.g. cellulosic or aramid), and then the imbibed paper issubjected to the electromagnetic field including in-line processingtreatment. Such in-line or off-line processing treatments will bepreferably performed in a way that maximize the exposure of the oil tothe electromagnetic field such as reducing gradients, mainly temperatureand/or electromagnetic radiation flux, within the bulk of the materialtreated. Falling film transfer equipment and/or droplet chambers aresuitable.

A fourth aspect of the invention is a dielectric material comprising anorganic fibrous structure (e.g. woven tissues or textiles or non-woven)impregnated with at least 1 wt % of a vegetable triacylglycerol,preferably a soy oil, in which at least 70%, preferably at least 75% ofthe fatty acids are C₁₄ to C₂₂ mono-unsaturated, and less than 16%,preferably less than 7%, more preferably less than 6% of the fatty acidsare polyunsaturated.

The vegetable triacylglycerol used for impregnation may be any of thefluids for use according to the invention described herein.

In a preferred embodiment, the organic fibrous structure is a non-wovenmade of cellulosic or aramid fibres, polyimides, polyphenylsulfones,polyamides, polyesters (e.g. PET) and polyethylene and combinationtherewith in various forms composites, laminates and tailoredmorphologically tailored surfaces and/or multidimensional structures andhybrids/mixtures thereof.

The vegetable triacylglycerol is preferably present at about 1 wt %-10wt %, more preferably 10 wt % to about 50 wt %, even more preferably ator about 20 wt % to 40 wt %.

In a fifth aspect, the invention provides a use of a vegetable oil as aheat-transfer dielectric fluid in a device to generate, store, convertand/or distribute electrical energy, wherein the vegetable oil is atriacylglycerol having at least one hydroxy fatty acid. Preferably thehydroxyl fatty acid is cis-12-hydroxyoctadec-9-enoic acid, preferablyhaving the D configuration at the chiral carbon. In a particularlypreferred embodiment all of the fatty acids in the triacylglycerol areD-cis-12-hydroxyoctadec-9-enoic acid (Castor oil or ricinoleic acid) andthis triacylglycerol is mixed in varying proportions with atriacylglycerol in which at least 70%, preferably at least 75% of thefatty acids are C₁₄ to C₂₂ mono-unsaturated, and less than 16%,preferably less than 7%, more preferably less than 6% of the fatty acidsare polyunsaturated. Preferably, in a blend, the castor oil representsfrom 5 to 15% of the triacylglycerol.

The term “high oleic soybean” refers to soybean seeds that have an oleicacid content of at least 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%,69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%,83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, and 95%.Preferred high oleic soybean oil starting materials are disclosed inWorld Patent Publication WO94/11516, the disclosure of which is herebyincorporated by reference.

The term “high oleic oil” refers to an oil having an oleic acid contentof at least 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%,82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, and95%.

Useful examples of contents of polyunsaturated of the oil for the use ofthe present invention are less than 16%, 15%, 14%, 13%, 12%, 11%, 10%,9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%.

In a sixth aspect, the invention provides a blended high oleic oil withan improved Df value at a constant temperature comprising:

a) a first oil in the range of 1-100 vol % that is a high oleic soybeanoil; andb) a second oil in the range of 1-100 vol %; andc) wherein the blended high oleic oil has an oleic acid content of atleast 70%; and wherein the Df value, at a constant temperature, of theblended high oleic oil is improved when compared under the sameconditions to an oil not comprising the high oleic soybean oil.

Useful examples of percent volume for the oils a) and b) of the blendedoil of the invention are 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%,12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%,26%, 27, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%,40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%,54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%,68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%,82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%,96%, 97%, 98%, 99%, and 100%. The amount of oil which can be used willdepend upon the desired properties sought to be achieved in theresulting final blended oil product.

In a seventh aspect, the invention provides a blended high oleic oilwith an improved Df value at a constant temperature comprising:

a) a first oil in the range of 1-100 vol % that is a high oleic soybeanoil; andb) a second oil in the range of 1-100 vol % that is a mono-alkyl esterof oleic acid; andc) a third oil in the range of 1-100 vol %; andd) wherein the blended high oleic oil has an oleic acid content of atleast 70%; and wherein the Df value, at a constant temperature, of theblended high oleic oil is improved when compared under the sameconditions to an oil not comprising the high oleic soybean oil and/orthe purified esters of oleic acid.

Useful examples of percent volume for the oils a), b) and c) of theblended oil of the invention are 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%,10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%,24%, 25%, 26%, 27, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%,38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%,52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%,66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%,80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%,94%, 95%, 96%, 97%, 98%, 99%, and 100%. The amount of oil which can beused will depend upon the desired properties sought to be achieved inthe resulting final blended oil product.

The oil b) that is a mono-alkyl ester of oleic acid can be anyC₁-C₁₂alkyl ester of oleic acid. Particularly preferred are C₁-C₈alkylesters, more preferably C₁-C₆alkyl esters, such as methyl, ethyl,propyl, butyl, pentyl and hexyl esters, both straight and branched.

The oil described herein was tested for its suitability as aheat-transfer dielectric fluid by measuring the dielectric dissipationloss, Df. Df is an important parameter to compare fluids used fordielectric insulation and/or heat transfer in the presence of electricaland/or magnetic fields.

The dielectric dissipation loss, Df, in part, represents the tendency ofthe fluid in an alternating electromagnetic field to depart from theideal of a pure dielectric medium in which no energy dissipation losseswould occur. The dielectric loss typically increases with the presenceof impurities in the fluid, especially charged impurities, with increasein water content, with free acids and with molecular breakdown of thefluid into smaller species. Furthermore, the stability of the dielectricloss versus temperature within a representative temperature range is aninsurance of a durable fluid composition exhibiting good performanceover prolonged period of time (i.e. good aging behaviour).

The measurement of Df is made using ASTM D924, and is based on thesuperheterodyne principle.

In one aspect the soy oil or blended oil for use according to theinvention preferably shows a Df of less than at or about 1.2×10⁻³ whenmeasured at 23° C., preferably less than at or about 5.4×10⁻³ whenmeasured at 70° C., preferably less than 9.1×10⁻³ when measured at 90°C., preferably less than at or about 1.21×10⁻² when measured at 100° C.,preferably less than at or about 1.95×10⁻² when measured at 120° C.,preferably less than at or about 2.32×10⁻² when measured at 130° C., andpreferably, it shows a Df of less than at or about 2.32×10⁻² over atemperature range of at or about 23-130° C.

In another aspect the soy oil or blended oil for use according to theinvention preferably shows a Df of less than at or about 2.5×10⁻⁴ whenmeasured at 23° C., preferably less than at or about 2.5×10⁻³, morepreferably less than at or about 1.5×10⁻³ when measured at 70° C.,preferably less than at or about 5×10⁻³, more preferably less than at orabout 3×10⁻³ when measured at 90° C., preferably less than at or about7×10⁻³, more preferably less than at or about 4×10⁻³ when measured at100° C., preferably less than at or about 2×10⁻², more preferably lessthan at or about 7×10⁻³ when measured at 120° C., and preferably lessthan at or about 2×10⁻², more preferably less than at or about 1×10⁻²when measured at 130° C. Preferably, it shows a Df of less than at orabout 2×10⁻², more preferably less than at or about 1×10⁻² over atemperature range of at or about 23-130° C.

In one aspect for the use according to the invention, a blended oil maybe used. Such blends are made by blending a high oleic soy oil having anoleic acid content of at least 70%, preferably at least 75% with anotheroil, preferably a vegetable oil. The quantity of high oleic soy oil tobe added to another oil may be determined by titration: the high oleicsoy oil may be added until the blended oil has a Df of less than at orabout 1.2×10⁻³ when measured at 23° C., preferably less than at or about5.4×10⁻³ when measured at 70° C., preferably less than 9.1×10⁻³ whenmeasured at 90° C., preferably less than at or about 1.21×10⁻² whenmeasured at 100° C., preferably less than at or about 1.95×10⁻² whenmeasured at 120° C., preferably less than at or about 2.32×10⁻² whenmeasured at 130° C., and preferably, it shows a Df of less than at orabout 2.32×10⁻² over a temperature range of at or about 23-130° C.

The high oleic soy oil that is used for blending preferably has apolyunsaturated content of less than at or about 16%, more preferablyless than at or about 7%.

In another aspect for the use according to the invention, a blended oilmay be used. Such blends are made by blending a high oleic soy oilhaving an oleic acid content of at least 70%, preferably at least 75%with another oil, preferably a vegetable oil. The quantity of high oleicsoy oil to be added to another oil may be determined by titration: thehigh oleic soy oil may be added until the blended oil has a Df of lessthan at or about 2.5×10⁻⁴ when measured at 23° C., preferably less thanat or about 2.5×10⁻³, more preferably less than at or about 1.5×10⁻³when measured at 70° C., preferably less than at or about 5×10⁻³, morepreferably less than at or about 3×10⁻³ when measured at 90° C.,preferably less than at or about 7×10⁻³, more preferably less than at orabout 4×10⁻³ when measured at 100° C., preferably less than at or about2×10⁻², more preferably less than at or about 7×10⁻³ when measured at120° C., and preferably less than at or about 2×10⁻², more preferablyless than at or about 1×10⁻² when measured at 130° C. Preferably, theblended oil shows a Df of less than at or about 0.02, more preferablyless than at or about 1×10⁻² over a temperature range of at or about23-130° C. The high oleic soy oil that is used for blending preferablyhas a polyunsaturated content of less than at or about 16%, morepreferably less than at or about 7%.

A dynamic (natural or forced) heat transfer takes place in mostelectrical equipment cooled and electrically insulated with oils. Theheating of a liquid filled transformer must be controlled, in largeproportion by the coolant and dielectric fluid, taking into accountfairly large temperature variations, between the internal hotspots andthe external temperature extremes, in winter and in summer. Under goodcontrolled conditions the transformer can be in operation for more than30 years; but can also be quickly damaged with relatively smalldeviations, sometime less than 10° C., from the ideal operatingtemperature defined for each category of transformers and the energytransformation load for which they have been designed.

At least four important properties of the oil vary with temperature,each of them at various degrees leading to reversible or irreversibleproperty changes in the dielectric heat-transfer fluid (oil). Theseproperties are the density, the thermal conductivity, the dynamicviscosity (all three of which decrease with increasing temperature) andthe specific heat (which increases with increasing temperature).

For an oil temperature variation from 25° C. to 85° C., it is preferredthat the density change be less than at or about 5%, the conductivitychange be less than at or about 3%, the heat capacity change be lessthan at or about 10%. The viscosity change is by far the mostsubstantial, since it can reach 50% for the same range of temperature.

Therefore the viscosity, which contributes to the fluid mechanics viathe Re number (Reynold Re=(velocity.diameter.density)/viscosity),directly impacts the fluid's heat-transfer capability, yielding a poorerheat transfer when the viscosity increases and a better one if theviscosity decreases.

EXAMPLES Example 1 Transformation of Soybean (Glycine max) EmbryoCultures and Regeneration of Soybean Plants.

Soybean embryogenic suspension cultures are transformed by the method ofparticle gun bombardment using procedures known in the art (Klein et al.(1987) Nature (London) 327:70 73; U.S. Pat. No. 4,945,050; Hazel et al.(1998) Plant Cell. Rep. 17:765 772; Samoylov et al. (1998) In Vitro CellDev. Biol. Plant 34:8 13). In particle gun bombardment procedures it ispossible to use purified 1) entire plasmid DNA or, 2) DNA fragmentscontaining only the recombinant DNA expression cassette(s) of interest.

Stock tissue for transformation experiments are obtained by initiationfrom soybean immature seeds. Secondary embryos are excised from explantsafter 6 to 8 weeks on culture initiation medium. The initiation mediumis an agar solidified modified MS (Murashige and Skoog (1962) Physiol.Plant. 15:473 497) medium supplemented with vitamins, 2, 4-D andglucose. Secondary embryos are placed in flasks in liquid culturemaintenance medium and maintained for 7-9 days on a gyratory shaker at26+/−2° C. under ˜80 μEm-2s-1 light intensity. The culture maintenancemedium is a modified MS medium supplemented with vitamins, 2, 4-D,sucrose and asparagine. Prior to bombardment, clumps of tissue areremoved from the flasks and moved to an empty 60×15 mm petri dish forbombardment. Tissue is dried by blotting on Whatman #2 filter paper.Approximately 100-200 mg of tissue corresponding to 10-20 clumps (1-5 mmin size each) are used per plate of bombarded tissue.

After bombardment, tissue from each bombarded plate is divided andplaced into two flasks of liquid culture maintenance medium per plate ofbombarded tissue. Seven days post bombardment, the liquid medium in eachflask is replaced with fresh culture maintenance medium supplementedwith 100 ng/ml selective agent (selection medium). For selection oftransformed soybean cells the selective agent used can be a sulfonylurea(SU) compound with the chemical name, 2 chloro N ((4 methoxy 6 methyl1,3,5 triazine 2 yl)aminocarbonyl)benzenesulfonamide (common names:DPX-W4189 and chlorsulfuron). Chlorsulfuron is the active ingredient inthe DuPont sulfonylurea herbicide, GLEAN®. The selection mediumcontaining SU is replaced every week for 6-8 weeks. After the 6-8 weekselection period, islands of green, transformed tissue are observedgrowing from untransformed, necrotic embryogenic clusters. Theseputative transgenic events are isolated and kept in media with SU at 100ng/ml for another 2-6 weeks with media changes every 1-2 weeks togenerate new, clonally propagated, transformed embryogenic suspensioncultures. Embryos spend a total of around 8-12 weeks in contact with SU.Suspension cultures are subcultured and maintained as clusters ofimmature embryos and also regenerated into whole plants by maturationand germination of individual somatic embryos.

Example 2 Genetic Material Used to Produce the High Oleic Trait

A Soybean (Glycine max) event was produced by particle co-bombardment asdescribed in Example 1 with fragments PHP19340A (FIG. 10; SEQ ID NO: 1)and PHP17752A (FIG. 11; SEQ ID NO: 2). These fragments were obtained byAsc I digestion from a source plasmid. Fragment PHP19340A was obtainedfrom plasmid PHP19340 (FIG. 12; SEQ ID NO: 3) and fragment PHP17752A wasobtained from plasmid PHP17752 (FIG. 13; SEQ ID NO: 4). The PHP19340Afragment contains a cassette with a 597 by fragment of the soybeanmicrosomal omega-6 desaturase gene 1 (gm-fad2-1) (Heppard et al., 1996,Plant Physiol. 110: 311-319).

The presence of the gm-fad2-1 fragment in the expression cassette actsto suppress expression of the endogenous omega-6 desaturases, resultingin an increased level of oleic acid and decreased levels of palmitic,linoleic, and linolenic acid levels. Upstream of the gm-fad2-1 fragmentis the promoter region from the Kunitz trypsin inhibitor gene 3 (KTi3)(Jofuku and Goldberg, 1989, Plant Cell 1: 1079-1093; Jofuku et al.,1989, Plant Cell 1: 427-435) regulating expression of the transcript.The KTi3 promoter is highly active in soy embryos and 1000-fold lessactive in leaf tissue (Jofuku and Goldberg, 1989, Plant Cell 1:1079-1093). The 3′ untranslated region of the KTi3 gene (KTi3terminator) (Jofuku and Goldberg, 1989, Plant Cell 1: 1079-1093)terminates expression from this cassette.

The PHP17752A fragment contains a cassette with a modified version ofthe soybean acetolactate synthase gene (gm-hra) encoding the GM-HRAprotein with two amino acid residues modified from the endogenous enzymeand five additional amino acids at the N-terminal region of the proteinderived from the translation of the soybean acetolactate synthase gene5′ untranslated region (Falco and Li, 2003, US Patent Application:2003/0226166). The gm-hra gene encodes a form of acetolactate synthase,which is tolerant to the sulfonylurea class of herbicides. The GM-HRAprotein is comprised of 656 amino acids and has a molecular weight ofapproximately 71 kDa.

The expression of the gm-hra gene is controlled by the 5′ promoterregion of the S-adenosyl-L-methionine synthetase (SAMS) gene fromsoybean (Falco and Li, 2003, US Patent Application: 2003/0226166). This5′ region consists of a constitutive promoter and an intron thatinterrupts the SAMS 5′ untranslated region (Falco and Li, 2003). Theterminator for the gm-hra gene is the endogenous soybean acetolactatesynthase terminator (als terminator) (Falco and Li, 2003, US PatentApplication: 2003/0226166).

Example 3 Transformation and Selection for the Soybean High Oleic Event

For transformation of soybean tissue, a linear portion of DNA,containing the gm-fad2-1 gene sequence and the regulatory componentsnecessary for expression, was excised from the plasmid PHP19340 throughthe use of the restriction enzyme Asc I and purified using agarose gelelectrophoresis. A linear portion of DNA, containing the gm-hra genesequences and the regulatory components necessary for expression, wasexcised from the plasmid PHP17752 through the use of the restrictionenzyme Asc I and purified using agarose gel electrophoresis. The linearportion of DNA containing the gm-fad2-1 gene is designated insertPHP19340A and is 2924 by in size. The linear portion of DNA containingthe gm-hra gene is designated insert PHP17752A and is 4511 by in size.The only DNA introduced into transformation event DP-305423-1 was theDNA of the inserts described above.

The transgenic plants from event DP-305423-1 were obtained bymicroprojectile bombardment as described in Example 1. Embryogenictissue samples were taken for molecular analysis to confirm the presenceof the gm-fad2-1 and gm-hra transgenes by Southern analysis. Plants wereregenerated from tissue derived from each unique event and transferredto the greenhouse for seed production.

Example 4 Southern Analysis of Plants Containing the High Oleic Event

Materials and Methods: Genomic DNA was extracted from frozen soybeanleaf tissue of individual plants of the T4 and T5 generations of DP305423 1 and of control (variety: Jack) using a standard Urea ExtractionBuffer method. Genomic DNA was quantified on a spectrofluorometer usingPico Green® reagent (Molecular Probes, Invitrogen). Approximately 4 μgof DNA per sample was digested with Hind III or Nco I. For positivecontrol samples, approximately 3 pg (2 genome copy equivalents) ofplasmid PHP19340 or PHP17752 was added to control soybean genomic DNAprior to digestion. Negative control samples consisted of unmodifiedsoybean genomic DNA (variety: Jack). DNA fragments were separated bysize using agarose gel electrophoresis.

Following agarose gel electrophoresis, the separated DNA fragments weredepurinated, denatured, neutralized in situ, and transferred to a nylonmembrane in 20×SSC buffer using the method as described forTURBOBLOTTER™ Rapid Downward Transfer System (Schleicher & Schuell).Following transfer to the membrane, the DNA was bound to the membrane byUV crosslinking.

DNA probes for gm-fad2-1 and gm-hra were labelled with digoxigenin (DIG)by PCR using the PCR DIG Probe Synthesis Kit (Roche).

Labelled probes were hybridized to the target DNA on the nylon membranesfor detection of the specific fragments using DIG Easy Hyb solution(Roche) essentially as described by manufacturer. Post-hybridizationwashes were carried out at high stringency. DIG labelled probeshybridized to the bound fragments were detected using the CDP-StarChemiluminescent Nucleic Acid Detection System (Roche). Blots wereexposed to X ray film at room temperature for one or more time points todetect hybridizing fragments. The fatty Acid composition of the eventwas determined as described in Example 2. Oleic acid levels determinedin 29 different events (T1 generation) ranged from 61.5-84.6%. Oleicacid level from one event (T4-T5 generation) ranged from 72-82%.

Example 5 Fatty Acid Contents and Compositions

Qualitative and quantitative fatty acid compositions of oils weredetermined using modifications of AOCS Ce 2-66 (Preparations of methylesters of fatty acids) and AOCS Ce 1e-91 (Determination of fatty acidsin edible oils and fats by capillary GLC) official methodologies asfollows. Oil stocks were prepared by adding 0.5000 gm (weighed andrecorded to an precision of 0.0001 g) of oil and 0.0130 g to 0.0260 g(weighed and recorded to an precision of 0.0001 g) of internal standard(tri-pentadecanoin; NuChek Prep; Elysian Minn., USA) to a 10 mlvolumetric flask; the internal standard was omitted where the analysiswas limited to qualitative (area %) data. Seven ml heptane was added andthe stock was sonicated for 2 min to ensure full dissolution of theInternal Standard Powder (IST) powder. After cooling to room temperaturethe stock was brought to volume with heptane. Stocks were preparedimmediately prior to analysis. Dilution series of the oils stocks werethen prepared by adding 0, 50, 100, (4×150), 200, 250, and 300 ul(˜0-0.0150 g oil per tube) of the oil stock to pre-labelled tubes (glass13×100 mm with Teflon lid inserts; VWR 53283 800 tubes, 60826-304 caps;VWR Bridgeport N.J., USA) and bringing each sample to a final volume of300 ul with heptane. The tubes were prepared for derivatization bywrapping the threaded portions with PTFE sealant tape. Derivatizationwas performed as follows: The tubes were vortex mixed and 1 mL ofderivatization acid stock (prepared by adding 5 mL acetyl chloride(Fluka 00990; Sigma Aldrich St Louis Mo., USA) to 50 ml ice-coldanhydrous methanol) was added. The tubes were capped tightly, re-vortexand incubated at 80° C. in a heat block for 1 hr. The tubes were cooledto room temp and 1 mL of aqueous 1M NaCl was added followed 0.5 mLheptane. The samples were vigorously vortex mixed and the phases wereallowed to separate prior to transferring ˜200 uL of the upper (heptane)phase to a GC sample vial fitted with a liner (Part # 225350-631SP;Wheaton, Millville N.J., USA). Samples were analyzed by GC as follows.An Agilent 6890 fitted with an Omegawax 320 (Supelco, Bellefonte Pa.,USA) capillary column (30 m×0.32 mm ID; 0.25 um film thickness). One ulsamples were injected at a 10:1 split ratio into the GC inlet which washeated to 250° C. Hydrogen was used as the carrier gas at a linearvelocity of 39 cm/sec (constant flow mode). The initial oven temperaturewas 160° C. for 4 min and the oven temperature was then ramped to 220°C. at 2 C/min and was then held at the final temperature for 10 min(total run time 44 min). Detection was by flame ionization and a NuChekPrep 461 Standard (1:100 dilution in heptane; NuChek Prep; ElysianMinn., USA) was used to identify peaks, by co-chromatography. All peakswith an area >0.01% were included in the analysis.

Tocopherol Analysis

Tocopherol contents were measured according to AOCS Official Method Ce8-89 on an Agilent 1100 HPLC system fitted with a 250×4 mm Lycoshere Si60 (5 um) analytical column and a G1321A fluorescence detector. Oilstocks, as described above, without internal standard were used for thisanalysis. Quantitative standards dissolved in heptane, were preparedwith authentic α (alpha), β (beta), γ (gamma) and δ (delta) tocopherolstandards (Supelco, Bellefonte Pa., USA). Standard concentrations wereconfirmed by UV-spectroscopy using the following wavelengths andextinction coefficients [α (alpha), OD292, 0.0076; β (beta) OD296,0.0089; γ (gamma) OD298, 0.0091; δ (delta) OD298, 0.0087].

Oil Quality and Oxidative Stability Measurements Free Fatty Acid Content

Free fatty acid contents of the oils were performed by titration using aMettler-Toledo DL22 F&B titrator (Mettler-Toledo, Columbus Ohio, USA)according to the manufacturers protocol M345 (Acid Number of edibleoils).

Peroxide Value

Peroxide values of the oils were performed by iodometric titration usinga Mettler-Toledo DL22 F&B titrator (Mettler-Toledo, Columbus Ohio, USA)according to the manufacturers protocol M346 (Peroxide value in edibleoils and fats).

p-Anisidine Value

p-Anisidine values were determined on oils according to AOCS officialmethod Cd 18-90.

Oxidative Stability Index

The oxidative stability index was measured on 5.0+/−0.2 g samples ofpure oil samples (with or without additives) according to AOCS officialmethod Cd 12b-92, using an OSI-24 Oxidative Stability Instrument.Instrument control and data analysis were performed using OSI Programv8.18 and Instacal 5.33 software (Omnion, Inc, Rockland Mass., USA).

TABLE 1 Fatty acid profiles of some soy oils 16:0 18:0 18:1 18:2 % Totalpoly- % % % % 18:3 % unsaturates Commodity Soy 8-13 2-6 18-27 51-59 6-1057-69 Oil¹ E1, an example of 6-7  4-5 70-86  2-13 2-3   4-16 the rangeof High Oleic Soy Oils for use according to the invention For thistable, fatty acid % relates the individual fatty acid to the sum of thefive major fatty acids indicated. Other fatty acid types that aresometimes present and represent less than 3% of the total fatty acidsare not considered for purposes of comparison ¹Value ranges for the fivemajor fatty acids in commodity soy oil are taken from “The LipidHandbook” 2nd ed., (1994) Gunstone, F. D., Harwood, J. L., Padley, F.B., Chapman & Hall. 16:0 = palmitic acid, 18:0 = stearic acid, 18:1 =oleic acid, 18:2 = linoleic acid, 18:3 = linolenic acid

Example 6 Dielectric Loss

The loss factor (Df) was measured using ASTM D924 for the dielectricheat-transfer fluids shown in Table 2, at different temperatures. Lossfactor was plotted VS temperature.

The results are shown in FIG. 1, wherein the squares ▪ and triangles ▴show the loss factor for comparative fluid C1 (measured at two differenttimes), the crosses X show the loss factor for comparative fluid C2, thediamonds ♦ show the loss factor for a soybean oil for use according tothe invention E1, and the filled circles  show the loss factor formineral oil, which is included as a reference.

TABLE 2 Dielectric heat-transfer fluids used for experiments TocopherolFatty acid composition % content Reference Fluid C16:0 C18:0 C18:1 C18:2C18:3 mg/100 g oil C1 Envirotemp ® 10 4   23-48 34-54 1-8 140 FR3 ™fluid (soy oil) (Cooper Industries, Inc.) C2 BIOTEMP ® (Total 84-8510-12 0-3  46 (sunflower) saturates) Biodegradable 3-8 DielectricInsulating Fluid (ABB, Inc.) E1 One of the 6.15 3.85 77.74 4.20 2.19 97mg/100 ml soybean oil s (fluid for the use of the invention)

TABLE 3 Detailed fatty acid composition of dielectric heat-transferfluid E1 used for experiments Fatty acid % C14:0 (myristic) 0.04 C15:0(pentadecanoic) 0.03 C16:0 (palmitic) 6.15 C16:1 n-7 (palmitoleic) 0.10C17:0 (margaric) 0.81 C18:0 (stearic) 3.85 C18:1 n-9 (oleic) 77.74 C18:1(octadecenoic), 1.30 C18:2 n-6 (linoleic) 4.20 C18:3 n-3(alpha-linoleic) 2.19 Total polyunsaturates 0.39 C20:0 (arachidic) 0.38C20:1 n-9 (eicosenoic) 0.40 C20:1 n-9 (eicosadienoic) 6.79 C22:0(behenic) 0.01 C24:0 (lignoceric) 0.16 Others 0.00

It is clear from FIG. 1 that the soybean oil for use according to theinvention (E1)) shows a low dielectric loss factor that stays relativelyconsistent with increase in temperature, whereas the other vegetableoils (C1 and C2) show significant increases in loss factor as thetemperature is increased.

The results are shown in tabular form in Table 4.

TABLE 4 Df for oil E1 at various temperatures Temperature (° C.) Df 23  2 × 10⁻⁴ 70 1.4 × 10⁻³ 90 2.7 × 10⁻³ 100 3.6 × 10⁻³ 120 6.5 × 10⁻³ 1308.1 × 10⁻³

Example 7 Breakdown Voltage

The dielectric breakdown voltage is an essential parameter to comparefluids used for dielectric insulation and/or heat exchange in thepresence of electrical and magnetic fields. It is also a relevantindication of the arcing transmission characteristics of the fluid.

The dielectric breakdown voltage, measured according to ASTM D877,characterises the dielectric performance limit of the fluid, which is abulk property giving indirect access to the ultimate voltage under whichthe dielectric can be used and its ability to sustain eventual voltagepulses.

The soy oil for use according to the invention (E1) has a breakdownvoltage at 23° C. within the range of 57 to 66 kV. In contrast, the twocomparative fluids C1 and C2 have breakdown voltages in the range of 47to 65 kV at 25° C., i.e. significantly broader and lower. The fluid foruse according to the invention (E1) is clearly superior, exhibitingbetter consistency versus arcing transmission as well.

Example 8 Pre-Treatment Method

The fluid for the use according to the invention (E1) as well as the twocomparative fluids (C1 and C2) of a mass of 2.6 g were exposed to acommercial microwave treatment of one minute at a maximum power of 900W. Such conditions were selected to yield a fluid temperature inferiorto 200° C. and preferably lower than 160° C. in order to maintain themolecular integrity of the essential components of the fluid.

Example 9 Differential Scanning Calorimetry and ThermogravimetricAnalysis

In order to demonstrate the benefit of the pre-treatment method byelectromagnetic microwave exposure (Example 8), various vegetabledielectric heat-transfer fluids were subjected to differential scanningcalorimetry coupled with thermogravimetric analysis, both with andwithout the pre-treatment.

Specific conditions and equipment references are provided below:

Equipment: 2960 SDT-CE5275 Ta Instrument (simultaneously performingDSC-TGA—differential scanning calorimetric and thermogravimetricanalysis)Test conditions:

-   -   10° C./min till 650[° C.]    -   air flow: 100 ml/min    -   air composition

N₂: 78.09% O₂: 20.95% Ar: 0.93% CO₂: 0.03

FIG. 2 shows the thermo-gravimetric pattern and heat flux generatedbefore (dotted lines) and after (solid lines) a pharmaceutical grade ofRicinoleic oil is exposed to the electromagnetic microwave treatment ofExample 8.

The heat flux signal definition and their relative strength clearly showa beneficial preconditioning of the oil by the electromagnetic microwavetreatment process and method therewith, as is shown for example by thesharpness of the peaks, the start and the onset temperatures after thepre-treatment.

FIG. 3 shows the thermo-gravimetric pattern and heat flux generatedbefore (dotted lines) and after (solid lines) a commercial grade of HighOleic Sunflower oil, the comparative fluid C2, is exposed to theelectromagnetic microwave treatment of Example 8.

The heat flux signal definition and their relative strength clearly showa beneficial preconditioning of the oil by the electromagnetic microwavetreatment process and method therewith, as is shown by the sharpness ofthe peaks after the pre-treatment.

FIG. 4 shows the thermo-gravimetric pattern and heat flux generatedbefore (solid lines) and after (dotted lines) a commercial grade ofnormal soybean oil, the comparative fluid C1, was exposed to theelectromagnetic microwave treatment of Example 8.

The heat flux signal definition and their relative strength clearly showa beneficial preconditioning of the oil by the electromagnetic microwavetreatment process and method therewith, as is shown by the sharpness ofthe peaks after the pre-treatment.

FIG. 5 shows the thermo-gravimetric pattern and heat flux generatedbefore (solid lines) and after (dotted lines) the fluid for the use ofthe invention, E1, was exposed to the electromagnetic microwavetreatment of Example 8.

The heat flux signal definition and their relative strength clearly showa beneficial preconditioning of the oil by the electromagnetic microwavetreatment process and method therewith, as is shown by the sharpness ofthe peaks after the pre-treatment.

Note: the beneficial effect of the pre-treatment extends to alltriacylglycerol dielectric heat-transfer fluids and mixtures thereof,and is not limited to the fluid used in the use according to theinvention.

Example 10 Behaviour of Dielectric Heat-Transfer Fluid with DielectricPaper

Commercially available transformer insulation Kraft paper, from WeidmannAG, Rapperswill, Switzerland, was impregnated at room temperature, via anaturally occurring imbibing process, with an amount equivalent to 30 wt% of the fluid for use according to the invention. The initial specificweight of the paper was 95 g/m².

One sample of such imbibed paper was subjected to the microwavepre-treatment method of Example 8, and a second was not.

FIG. 6 shows the thermal behaviour of untreated Kraft paper (solidline), Kraft paper imbibed with the fluid for use according to theinvention (dotted lines) and Kraft paper imbibed with the fluid for useaccording to the invention and pre-treated with microwaves according toExample 8 (dash-dot lines).

The imbibing of the Kraft paper with the fluid for use according to theinvention results in an enhancement of the thermal resistance of thepaper by 20-40° C. The microwave pre-treatment results in a furtherenhancement by 10° C.

The impregnation can be done during the manufacture of the paper orafter. The microwave treatment can be repeated as many times as neededand can be performed by exposing said fluid to a constant and uniformlydistributed electromagnetic field applied continuously or in series ofconstant and/or variable pulse and relaxation sequences; repeating theexposure sequence as often as needed. Inventor found for example thatthe exposure of 7.2 g of oil of the invention to 20 cycles of 10 s 300W-microwave pulse and 50s relaxation were effective in preconditioningthe oil without causing damage that may be provoked by prolongedhigher-microwave-power exposure.

The imbibing oil can be any oil mixtures of the invention. An oil of theinvention mixed with 20% of a commodity linseed oil has surprisinglyshown good sealing properties that are especially valuable in sealedelectrical devices of the invention, especially transformers, which tendto micro-leak with time, especially for those used for relatively longperiod of time, such as 20 to 30 years. The sealing nature of the oil ofthe blends of the invention is especially appreciated. Naturallyoccurring or synthesised epoxidized vegetable oil have also been foundas exhibiting similar sealing effect of the insulating paper as well asat sealing interfaces.

The paper treatment with the oil of the invention and/or mixturesthereof, has valuable effect on the viscoelastic behaviour of the paperand its mechanical resistance to puncture and tearing, for example;leading to enhance paper endurance appreciated to extend the life of theelectrical device, such as liquid filled transformers.

Example 12

It was found that under moderate ageing (88 hours at 170° C. in an airventilated oven) the dynamic viscosity of a conventional commodity soyoil having about 21% monounsaturated C18/1, increased irreversibly from60 to 180 mPa·s as measured at 23° C. Furthermore, the conventional oilshowed a strong colour change from a pale yellow to a rosewood colour.This represents a 3× increase in dynamic viscosity over a relativelyshort period of time. Such an increase in dynamic viscosity could leadto a 25% adjustment need of the circulated volume and pressure dropcompensation within a transformer.

An oil for use according to the invention, E1, was subjected to the sameheat aging, and no change in dynamic viscosity was observed.

This kind property makes the oil particularly useful as a dielectricheat-transfer fluid.

Example 13

An experiment was done to determine the effect of oleic acid content onDf vs temperature behaviour.

A given amount of a low linoleic soy oil (LL) having the fatty acidcomposition (“FAC”) profile given in Table 6 was blended with an oil forthe use of the invention, E4, of the profile given in Table 6 to produceblended oils corresponding to 70% and 65% oleic acid oil mixtures of theFAC profile given in Table 6. A commodity soy oil sample (Cm) of the FACprofile given in Table 6 served as a representative of a lower oleic oilcontent sample.

TABLE 6 FAC of various soy oils and blended soil oils used for Example13. 70% 65% FAC, Relative % E2 E4 oleic oleic LL Cm C14 (Myristic) 0.040.04 0.04 0.05 0.07 0.07 C15 (Pentadecanoic) 0.03 0.03 0.03 0.03 0.020.02 C16 (Palmitic) 6.15 6.26 6.68 7.12 10.37 10.27 C16:1n7(Palmitoleic) 0.10 0.09 0.08 0.09 0.1 0.09 C17 (Margaric) 0.81 0.74 0.70.64 0.11 0.10 C17:1 1.35 0.01 1.06 0.96 0.07 0.06 C18 (Stearic) 3.853.94 4.09 4.19 4.77 4.59 C18:1n9 (Oleic) 77.74 74.36 69.24 64.53 20.9621.29 C18:1 Octadecenoic 1.30 1.17 0.89 0.9 1.44 1.43 C18:2n6 (Linoleic)4.20 8.7 12.74 17.06 57.01 53.46 C18:3n3 (alpha- 2.19 2.92 2.82 2.853.02 7.21 Linolenic) C20 (Arachidic) 0.39 0.37 0.37 0.36 0.35 0.35C20:1n9 (Eicosenoic) 0.38 0.29 0.27 0.26 0.17 0.19 C20:2n6 0.40 0.350.35 0.35 0.37 0.36 Eicosadienoic Total 6.79 11.97 15.91 20.26 60.461.03 polyunsaturates C22 (Behenic) 0.01 0.0 0 0 0.01 0.37 C24(Lignoceric) 0.16 0.10 0.07 0.07 0.1 0.13 C24:1 0.00 0 0 0 0 0 Other0.90 0.63 0.57 0.54 1.06 0.01

Samples of the oils and blends listed in Table 6 were submitted to theDf analysis as described in Example 6, measuring Df as a function oftemperature, at temperatures ranging from 23 to 130° C.

FIGS. 7A and 7B show the variation of Df as a function of temperaturefor the oils and blended oils listed in Table 6. FIG. 7A shows oils ofthe invention comprising 78% oleic acid (E2,) compared to commodity oiland a 65% oleic acid blend and a 70% oleic acid blend. FIG. 7B showsoils of the invention comprising a 74% oleic acid content (E4) comparedto commodity oil and a 65% oleic acid blend and a 70% oleic acid blend.

In FIG. 7A the squares designate the results for E2 (“HOSO”), having77.74% oleic acid.

The X; s in FIG. 7B designate the results for E4, having 74.36% oleic(74%);

The asterisks in Figures A and B designate the results for the commoditysoy oil (Cm) having 21% oleic acid and 61% polyunsaturates.

The triangles designate the results for a soy oil blend having 70% oleicand 16% polyunsaturates in FIGS. 7A and 7B.

The diamonds designate the results for a soy oil blend having 65% oleicand 20% polyunsaturates in FIGS. 7A and 7B.

It is clear from FIGS. 7A and 7B that the oils for use according to theinvention E1 show superior behaviour over the other oils, in that the Dfis lower and stays lower over the entire temperature range of 23-130° C.Furthermore, the oils of the invention E1, such as for example the 70%oleic acid blend, the oil E2 and oil E4 show less increase in Df withtemperature.

The commodity soy oil Cm without antioxidants and other additivesresponds similarly to the commercial soy oil C1 containing traditionaladditives for the transformer applications.

FIG. 8 shows the variation of Df as a function of the oleic content inpercent, at two temperatures (130° C., upper line, and 90° C., lowerline). It can be seen from FIG. 8 that at both temperatures the Df dropsas the oleic acid content increases, with a sharp decrease from at orabout 65% oleic acid to at or about 70% oleic acid. The oil used forthis experiment was oil E2 as an example for one of the oils of theinvention.

Example 14

An additional experiment was done to measure Df as a function oftemperature (according to Example 6) using two different soy oils foruse according to the invention, E2 and E4, as compared with high oleicsunflower oil (84% oleic acid, 8% total polyunsaturates), and oils C1and C2. The FAC of the oils is listed in Table 7.

TABLE 7 FAC of oils used in experiments of Example 14 High Oleic Oil E2E4 Sunflower C1 C2 FAC, Relative % C14 (Myristic) 0.04 0.04 0.03 0.070.04 C15 0.03 0.03 0.01 0.02 0.01 (Pentadecanoic) C16 (Palmitic) 6.156.26 2.97 10.57 3.59 C16:1n7 0.10 0.09 0.07 0.09 0.09 (Palmitoleic) C17(Margaric) 0.81 0.74 0.03 0.10 0.03 C17:1 1.35 0.01 0.06 0.06 0.05 C18(Stearic) 3.85 3.94 2.95 4.35 2.93 C18:1n9 (Oleic) 77.74 74.36 84.2121.38 83.81 C18:1 1.30 1.17 0.59 1.44 0.23 Octadecenoic C18:2n6 4.208.70 7.15 53.68 7.19 (Linoleic) C18:3n3 (alpha- 2.19 2.92 0.10 7.21 0.17Linolenic) C20 (Arachidic) 0.39 0.37 0.26 0.33 0.27 C20:1n9 0.38 0.290.29 0.18 0.27 (Eicosenoic) C22 (Behenic) 0.4 0.35 0.88 0.01 0.82 C24(Lignoceric) 0.16 0.10 0.30 0.02 0.04 C24:1 0.00 0.00 0.02 0.00 0.00Other 0.91 0.63 0.08 0.49 0.46

The Df was measured at various temperatures according to Example 6. Theresults are listed in Table 8. The results clearly show that oils E2 andE4, which are soy oils for use according to the invention, showsignificantly lower Df's over the temperature range of 23-130° C., andshow less increase in Df at high temperatures than the comparative oils.The high oleic sunflower Df data are locally just in between E4 and C1,close to C1 indicating a significant variation of the high oleicsunflower Df values within the 23 to 130 C temperature range. The higholeic sunflower without antioxidants and other additives respondssimilarly to the commercial high oleic sunflower C2 containingtraditional additives for the transformer applications.

TABLE 8 Df for oils at various temperatures High oleic Temp C1 C2 E2 E4sunflower 23 0.0016 0.0007 0.0002 0.0018 0.0003 70 0.0081 0.0085 0.00140.0021 0.006 90 0.0146 0.0166 0.0027 0.0044 0.016 100 0.0201 0.02080.0036 0.0059 0.0154 120 0.0287 0.0372 0.0065 0.0128 0.0296 130 0.04020.0524 0.0081 0.0186 0.0302

FIG. 9 shows in graphic form the dielectric loss factor (Df) VStemperature for comparative fluids C1 and C2 and for oils E2 and E4,wherein the squares ▪ show the loss factor for comparative fluid C1, theopen triangles ▴ show the loss factor for comparative fluid C2, thediamonds ♦ show the loss factor for a soybean oil for use according tothe invention E2 and E4, lower line E2, upper line E4.

1. A use of a soy oil as a heat-transfer dielectric fluid in a device togenerate, store, convert and/or distribute electrical energy, whereinthe soy oil is one in which at least 70% of the fatty acids are C14 toC22 mono-unsaturated, and less than 16% of the fatty acids arepolyunsaturated.
 2. The use according to claim 1, wherein the soy oilhas less than 6% of polyunsaturated fatty acids.
 3. The use according toclaim 1 or 2, wherein the soy oil has at least 80% content ofmonounsaturated C₁₄ to C₂₂ fatty acids.
 4. The use according to anypreceding claim, wherein the soy oil has a saturated fatty acid contentof less than at or about 12%.
 5. The use according to any precedingclaim, wherein the soy oil has a saturated fatty acid content of lessthan at or about 10%.
 6. The use according to any preceding claim,wherein the soy oil has less than 4% of polyunsaturated fatty acids. 7.The use according to any preceding claim, wherein the monounsaturatedfatty acids are C₁₈ monounsaturated fatty acids.
 8. The use according toany preceding claim, wherein the monounsaturated fatty acids are oleicacid.
 9. The use according to any one preceding claim, wherein thepolyunsaturated fatty acids are C₁₈ fatty acids having two or threedouble bonds, preferably C18:2 and/or C18:3.
 10. The use according toany one preceding claim, wherein the soy oil has the following fattyacid content: at or about 6% C16:0, 3% C18:0, 86% C18:1, 2% C18:2 and 2%C18:3.
 11. The use according to any one preceding claim, wherein the soyoil has the following fatty acid content: at or about 6% C16:0, 4%C18:0, 79% C18:1, 4% C18:2, 2% C18:3.
 12. The use according to any onepreceding claim, wherein the soy oil has the following fatty acidcontent: at or about 7% C16:0, 4% C18:0, 70% C18:1, 13% C18:2, 3% C18:3.13. The use according to any one preceding claim, wherein the soy oilhas the following fatty acid content: at or about 6% C16:0, 4% C18:0,74% C18:1, 9% C18:2, 3% C18:3.
 14. The use according to any onepreceding claim, wherein the soy oil has the following fatty acidcontent: at or about 6% C16:0, 4% C18:0, 78% C18:1, 4% C18:2, 2% C18:3.15. The use according to any one preceding claim, wherein the soy oiladditionally comprises tocopherol antioxidants, at a concentration of atleast 85 mg/100 g of oil.
 16. The use according to claim 15, wherein thetocopherol is naturally occurring tocopherols.
 17. The use according toany one preceding claim, wherein the soy oil is derived from a seedplant that has been genetically manipulated to increase expression ofthe gene encoding oleoyl 12-desaturase.
 18. The use according to any onepreceding claim, wherein the content of C18:2 is less than at or about5%.
 19. A device to generate, store, convert and/or distributeelectrical energy, comprising: (a) a conducting material; (b) adielectric material; and (c) a heat-transfer dielectric fluid, which isa soy oil in which at least 75% of the fatty acids are C₁₄ to C₂₂mono-unsaturated, and less than 7% of the fatty acids arepolyunsaturated.
 20. A device according to claim 19, wherein the soy oilis the vegetable oil described in any one of claims 1-18.
 21. A deviceaccording to claim 19 or 20, wherein the dielectric material is paper orboard made of cellulose or aramid, polyimides, polyphenylsulfones,polyamides, polyesters (e.g. PET) and polyethylene and combinationtherewith in various forms such composites, laminates, morphologicallytailored surfaces and/or multidimensional structures andhybrids/mixtures thereof.
 22. A method for preconditioning aheat-transfer dielectric fluid which is a vegetable triacylglycerol,comprising the step: (a) exposing said fluid to a constant and uniformlydistributed electromagnetic field.
 23. The method according to claim 22,wherein the electromagnetic field is in the form of microwaves, whichare applied at sufficient power and for sufficient time to heat thevegetable triacylglycerol to at least at or about 100° C., but nothigher than at or about 170° C.
 24. A dielectric material comprising anorganic fibrous structure (e.g. woven or non-woven) impregnated with atleast 10% wt of a vegetable triacylglycerol and/or mixtures in which atleast 75% of the fatty acids are C₁₄ to C₂₂ mono-unsaturated, and lessthan 7% of the fatty acids are polyunsaturated.
 25. The dielectricmaterial of claim 24, wherein the vegetable triacylglycerol has lessthan 6% polyunsaturated fatty acids.
 26. A blended high oleic oil withan improved Df value at a constant temperature comprising: a) a firstoil in the range of 1-100 vol % that is a high oleic soybean oil; and b)a second oil in the range of 1-100 vol %; and c) wherein the blendedhigh oleic oil has an oleic acid content of at least 70%; and whereinthe Df value, at a constant temperature, of the blended high oleic oilis improved when compared under the same conditions to an oil notcomprising the high oleic soybean oil.
 27. The blended high oleic oil ofclaim 26, having a Df of less than at or about 1.2×10⁻³ when measured at23° C.
 28. The blended high oleic oil of claim 26, having a Df of lessthan at or about 5.4×10⁻³ when measured at 70° C.
 29. The blended higholeic oil of claim 26, having a Df of less than at or about 9.1×10⁻³when measured at 90° C.
 30. The blended high oleic oil of claim 26,having a Df of less than at or about 1.21×10⁻² when measured at 100° C.31. The blended high oleic oil of claim 26, having a Df of less than ator about 1.95×10⁻² when measured at 120° C.
 32. The blended high oleicoil of claim 26, having a Df of and less than at or about 2.32×10⁻² whenmeasured at 130° C.
 33. The blended high oleic oil of claim 26, having aDf of less than 2.32×10⁻² over a temperature range of at or about23-130° C.
 34. The blended high oleic oil of claim 26, having a Df ofless than at or about 2.5×10⁻⁴ when measured at 23° C.
 35. The blendedhigh oleic oil of claim 26, having a Df of less than at or about1.5×10⁻³ when measured at 70° C.
 36. The blended high oleic oil of claim26, having a Df of less than at or about 3×10⁻³ when measured at 90° C.37. The blended high oleic oil of claim 26, having a Df of less than ator about 4×10⁻³ when measured at 100° C.
 38. The blended high oleic oilof claim 26, having a Df of less than at or about 7×10⁻³ when measuredat 120° C.
 39. The blended high oleic oil of claim 26, having a Df ofand less than at or about 1×10⁻² when measured at 130° C.
 40. Theblended high oleic oil of claim 26, having a Df of less than 0.01 over atemperature range of at or about 23-130° C.
 41. A blended high oleic oilwith an improved Df value at a constant temperature comprising: a) afirst oil in the range of 1-100 vol % that is a high oleic soybean oil;and b) a second oil in the range of 1-100 vol % that is a mono-alkylester of oleic acid; and c) a third oil in the range of 1-100 vol %; andd) wherein the blended high oleic oil has an oleic acid content of atleast 80%; and wherein the Df value, at a constant temperature, of theblended high oleic oil is improved when compared under the sameconditions to an oil not comprising the high oleic soybean oil and/orthe purified oleic acid and/or any isolated components of the oil thatis required to improve the performance of the said high oleic blend. 42.The oil of any one of claims 26-41, wherein the oil comprises at leastone antioxidant, selected from the group consisting of: tocopherols,tocotrienols, naturally occurring tocopherols, naturally occurringtocotrienols, Lubrizol 7653, TBHQ, Decanox MPS-90, and/or natural plantextracts.